Figure 1. Human mAbs RVFV-140, RVFV-268, and RVFV-379 delivered prior to challenge significantly improve survival in rats exposed to pathogenic RVFV by inhalation.

(A) Experimental design. Rats pretreated (n = 42 total) 24 hours prior to exposure with 10 mg/kg control (purple) or RVFV (blue) human mAbs by i.p. injection. Rats were exposed via whole-body aerosol to pathogenic RVFV (average 500 PFU) at 0 dpi and monitored for morbidity. (B) Survival from aerosol challenge after a total of 4 separate experiments. The gray box indicates the clinical window of neurologic disease (6–10 dpi). (C) The mean change in weight and temperature from baseline across all experiments (n = 5), grouped by mAb. Data are shown as mean ± SD. (D) Rats were monitored for morbidity using a clinical scoring system. Healthy rats displayed no clinical symptoms and had normal temperature. Symptomatic animals displayed fever, ruffled fur, perforin staining, or had weight loss ≥5% baseline weight. Rats with neurological symptoms displayed circling, head tremor, paralysis, and seizure. Rats meeting euthanasia criteria were humanely euthanized. Log-rank (Mantel-Cox) test was used to compare survival curves between RVFV mAb and control. *P < 0.05; **P < 0.01; ***P < 0.001.